This invention concerns a retainer to keep the wheels on a bypass door from jumping off the track.
Bypass doors are now employed for many openings, such as closets. Such doors are sometimes referred to as sliding doors, even though they typically roll on wheels. In a typical opening, two or more doors are mounted on wheels that roll in parallel tracks. The tops of the doors are guided in parallel tracks. When the doors are closed, one door is against the right jamb, and the other door is against the left jamb. The doors can be opened from either edge since they roll in separate tracks. Although two doors is most common in an opening, one, three or more doors may be used.
Two principal types of wheels and tracks are used for bypass doors. Some tracks have a slot and the wheels have a central flange that fits into the slot. Such a wheel rolls on the surfaces on each side of the flange, which engage the two top surfaces of the track on opposite sides of the slot. Another type of track has a raised rib and a wheel for such a track has two flanges that straddle the track. Such a wheel rolls on the top of the rib on a surface between the two flanges. Such a rib may have parallel sides, a circular bead at the top, or have an arrow shaped cross section on which the wheel rolls. Tracks are commonly extruded aluminum or roll formed sheet steel.
A problem that sometimes occurs with such bypass doors is jumping of the wheels from the supporting track. This may occur if the door is pushed violently, which may dislodge it from the track. This is most likely to occur when the door slams hard against the jamb. This is at least an inconvenience since it is then necessary to place the door back on the track to operate satisfactorily.
Unfortunately, this can also be hazardous if the door drops far enough upon leaving track that the top guides no longer engage the upper track. This can permit the door to topple, with possible injury to anyone nearby. This is a particular problem in installations where the track is near the edge of a ledge, such as when the floor of a closet is elevated relative to the floor of the adjacent room. If the wheels should jump off the track in such an installation, the door can drop off the ledge and may then topple.
It is, therefore, desirable to provide some means for assuring that the door does not jump off the track. One type of anti-jump attachment for a door has been proposed. This attachment is used with a track having an arrowhead shape. The attachment has a U-shaped opening with a pair of barbed spring fingers that snap over the arrowhead. This attachment is permanently a part of the mounting bracket for the wheel.
It is common to provide a vertical adjustment for the wheels on a bypass door. This is provided since the height of openings is not uniform and it may be desirable to raise or lower a door to better fit the opening. It also occurs that the door jambs may not be plumb. In that event, it is desirable to raise or lower the wheels selectively to tilt the door slightly to have its edge parallel to the jamb against which the door closes.
If an attachment that prevents jumping of the door from the track is secured to the door, the ability to vertically adjust the door may be inhibited. It is, therefore, desirable to provide means for preventing a wheel from jumping the track, which is vertically adjustable with the wheel. It is also desirable to provide such a means that can be installed after the doors are in place. This gives the option of omitting the anti-jump device if desired, and may make door installation and adjustment easier. It is also desirable that the anti-jump device positively retain the door on the track, instead of just increasing the force that causes the wheels to jump from the track.